Know My Number
The first step in understanding high blood pressure is learning what your numbers mean. Blood pressure is measured with two numbers: systolic (the higher number) and diastolic (the lower number) (e.g., 120/80 mmHg):
- Systolic pressure occurs when your heart contracts.
- Diastolic pressure occurs when your heart relaxes and fills with blood.
- Blood pressure is measured using millimetres of mercury (mmHg), which is a standardized measurement of pressure.
The higher your systolic or diastolic blood pressure – and the longer it stays high – the greater the potential damage to your blood vessels.
| Systolic BP (the top number) |
Diastolic BP (the bottom number) |
|
|---|---|---|
| For most people | Less than 140 | Less than 90 |
| If you have diabetes | Less than 130 | Less than 80 |
| Selected people at high risk for heart disease* |
Less than 120 | — |
*This includes people with heart disease, some forms of kidney disease, age over 75 years, or at high risk for heart disease. You should discuss with your physician or pharmacist if this applies to you.